But her web of lies began to unravel when a hire purchase company called Mrs Cowan about a car she had never owned, asking why she had stopped making payments.

She investigated, and found a trail leading back to her sister. Yesterday Hall was jailed for 15 months at Edinburgh Sheriff Court after admitting the fraud.

After the hearing Mrs Cowan revealed that she spent three years trying to sort out the mess her sister had caused for her, including bank accounts, store cards, credit cards and mobile phone contracts.

She said of the jail sentence: "I'm shocked but I'm just so glad. This has gone on for so long and I am relieved it is finally over.

"I would have felt very let down by the justice system if she hadn't been jailed."

Mrs Cowan called her sister "the most materialistic person I have ever met." She added: "Maybe she was jealous. She is older than me and maybe things should be the other way around, with me needing money from her.

"If that's true I feel sorry for her, this is what she has ended up as. I do lover her deep down but I can't stand the sight of her."

The court had heard how Mrs Cowan, from Leven, Fife, was alerted around Christmas 2003 when a hire purchase company called her about a Ford Puma.

The company told her a Linda Hall - her maiden name - had made payments for a time but they were now overdue.

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Linda Cowan only found out about the scam when she received overdue payment notices

Mrs Cowan then discovered that Hall had used her identity to secure a £140,000 mortgage to move from her ex-council house to a four-bedroom home in Livingston, West Lothian.

The businesswoman had seen pictures of the property and listened to her sister talk of the move - unaware that her own credit was being used to fund it.

She contacted Hall's workplace - a care home in Edinburgh - only to find it was a "Linda Hall" working there. Hall had used her sister's details to secure the job.

Finally, Mrs Cowan obtained a report on her own credit history and was shocked to find that she had several black marks for missed payments - all courtesy of her sister.

Hall later wrote a letter to her younger sister, at the instruction of their father, in an attempt to apologise.

She said she used a false identity so her estranged ex-husband, currently serving life in prison, could not get his hands on any of her money.

Alan Jackson, for Hall, told the court his client was "remorseful" and would have to live with her actions for the rest of her life.

He said her scheme was not well thought out and had gone much further than originally intended. It had driven "a massive wedge" between her and her sister and parents.

Sheriff Noel Mc Partlin accepted Hall had had a difficult life but said the gravity of the crimes merited a custodial sentence.

He told her: "You have caused enormous difficulty for your sister, damaging her credit rating and giving her concern about her career.

"I accept that your life has not been free of problems and you have coped with many difficulties, but I don't think it is being suggested these were the direct cause of the offences."